Putter head

ABSTRACT

A putter head includes a head main body having a recess portion in a face surface of the putter head, and a face insert disposed in the recess portion. The face insert has a slit extending upward from a bottom face thereof In the bottom face, the slit may extend from the vicinity of a toe-side end thereof to the vicinity of a heel-side end thereof A bottom end of the slit may be located on a rear edge of the face insert. A ceiling face of the slit may be in a shape of an arch from the toe side to the heel side. The slit may be filled with a viscoelastic material.

CROSS-REFERENCE TO RELATED APPLICATION

This Application claims priority from Japanese Patent Application No.2011-4939 filed Jan. 13, 2011, which is incorporated herein by referencein its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to a putter head of a golf club, and moreparticularly to a putter head containing a face insert mounted in a facesurface of a head main body thereof.

The putter in golf is a club for use mainly for hitting a ball on agreen to roll the ball toward a cup. Japanese Patent ApplicationPublication No. 2007-117635 describes a putter head including a faceinsert for a face surface thereof in order to soften a feeling ofputting a golf ball.

Japanese Patent Application Publication No. 2001-62008 describes aputter head including a synthetic resin integrated with a bottom portionof the face surface of the putter head to enable a player to easilyapply top spin to the ball. However, because the synthetic resin foamhas a high temperature dependency, a degree of top spin applied to theball varies considerably depending on the temperature.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a putter head in whichwhen a ball is putted, back spin is reduced compared to an ordinaryputter and the top spin can be applied to the ball easily while thetemperature dependency of easiness of applying the top spin is low.

According to the present invention, there is provided a putter headhaving a face surface thereof comprising: a head main body; and a faceinsert disposed on the head main body as the face surface, wherein theface insert has a slit extending upward from a bottom surface thereof,and wherein the face insert has a front face portion positioned on aface-surface side relative to the slit and a rear face portion on abackward side relative to the slit, the front and rear face portionsbeing connected to each other through toe and heel sides of the faceinsert.

In the bottom face of the face insert, the slit may extend from thevicinity of a toe-side end thereof up to the vicinity of a heel-side endthereof.

The slit may be deepest at a central portion in a toe-to-heel directionof the face insert, and the slit may become shallower gradually or stepby step toward the toe side and the heel side from the central portionthereof.

The putter head may further comprise a viscoelastic material disposed inthe slit of the face insert.

The face insert of the putter head of the present invention includes theslit extending upward from the bottom surface, thereby, when this putterhits a ball, a bottom portion of the front face portion of the faceinsert is retracted to suppress back spin while facilitating the topspin to be applied easily. Accordingly, straight advancement of the hitball is improved. In addition, a player can apply different degrees oftop spin to the ball by hitting it by the center portion or the toe andheel portions of the face insert.

When the front face portion and the rear face portion of the face insertare connected at the toe and heel sides of the face insert, the faceinsert can have high strength and durability properties.

Accordingly, the slit preferably extends from the vicinity of thetoe-side end of the bottom face to the vicinity of the heel-side endthereof.

When the slit is filled with a viscoelastic material, a hitting soundand a feeling of hitting the ball can be adjusted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1( a) is an exploded perspective view of an embodiment of a putterhead according to the present invention.

FIG. 1( b) is a front view of the putter head of FIG. 1( a).

FIG. 1( c) is a cross-sectional view taken along the line C-C of FIG. 1(b).

FIG. 2 is a front view of the face insert shown in FIGS. 1( a) to 1(c).

FIG. 3 is a cross-sectional view taken along the line of FIG. 2.

FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 3.

FIG. 5 is a cross-sectional view of the face insert in which aviscoelastic body is charged in a slit thereof.

FIG. 6 is a cross-sectional view of an example of a face insert in aputter head according to the present invention.

FIG. 7 is a cross-sectional view of an example of a face insert in aputter head according to the present invention.

FIG. 8 is a cross-sectional view of an example of a face insert in aputter head according to the present invention.

FIG. 9( a) is a cross-sectional view in a face to back direction showingan example of a face insert in a putter head according to the presentinvention.

FIG. 9( b) is a cross-sectional view in a face to back direction showingan example of a face insert in a putter head according to the presentinvention.

FIG. 10 is a cross-sectional view of another embodiment of a putter headaccording to the present invention.

FIG. 11( a) is a front view of still another embodiment of a putter headaccording to the present invention.

FIG. 11( b) is a cross-sectional view taken along the line B-B of FIG.11( a).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of a putter head according to the present invention will bedescribed in detail with reference to the accompanying drawings.

A putter head 1 as the first embodiment of the present invention isillustrated in FIGS. 1 to 4. This putter head 1 includes a head mainbody 2 having a recess portion 2H in the front face or face surfacethereof and a face insert 3 disposed within this recess portion 2H.According to this embodiment, the head main body 2 is made of such ametal as aluminum alloy, titanium alloy, copper alloy, or stainlesssteel. The face insert 3 is made of such a synthetic resin as polyester,nylon, urethane or such a metal as aluminum alloy, copper alloy, orstainless steel. A front face of the face insert 3 is aligned with thefront face of the head main body 2 around the recess portion 2H.

The recess portion 2H and the face insert 3 are of a substantiallyrectangular shape which is horizontally long. The depth of the recessportion 2H is entirely even and the thickness of the face insert 3 isentirely even. However, they may be provided partly with a deep portionor a thick portion or conversely may be provided partly with a shallowportion or a thin portion.

The lateral and vertical widths of the face insert 3 are slightlysmaller than those of the recess portion 2H and there is a slight gap 4between top, bottom, right and left side faces 3S of the face insert 3and a peripheral face 2S of the recess portion 2H. Preferably, the widthof this gap is 0.3 to 1.5 mm, and more preferably 0.4 to 1.0 mm.Regarding the size of the face insert 3, a vertical width H₀ is 16 to 30mm, particularly 18 to 25 mm, a lateral width W_(o) is preferred to be50 to 150 mm, particularly 70 to 100 mm, and a thickness thereof ispreferred to be 2 to 10 mm, and more preferably 3 to 8 mm. However, theyare not limited to these values.

As illustrated in FIGS. 2 to 4, this face insert 3 has a slit 3 a whichis cut in upward from a bottom face thereof. In the bottom face of theface insert 3, the slit 3 a extends from the vicinity of a toe-side endthereof up to the vicinity of a heel-side end thereof. The slit 3 a doesnot reach any side faces on the toe side and the heel side of the faceinsert 3. A front face portion on a forward (face) side relative to theslit 3 a and a rear face portion on a backward side relative to the slit3 a are continuous to each other through the toe-side end portion andthe heel-side end portion of the face insert 3. Bottom faces of thetoe-side end portion and the heel-side end portion of the face insert 3are flush with the bottom faces of the front face portion and the rearface portion of the face insert 3.

This slit 3 a is deepest in the vicinity of the center in a toe-to-heeldirection (right-to-left direction in the front view of the putterhead), while it becomes shallower gradually toward the toe side and theheel side from the vicinity of the center. According to this embodiment,as illustrated in FIG. 4, a ceiling face of the slit 3 a is of asubstantially semi-elliptical arch.

In this embodiment, preferably, a length W₁ in the toe-to-heel directionof the slit 3 a is 80 to 98% the length in the toe-to-heel direction ofthe face insert 3, and more preferably 85 to 90%.

According to this embodiment, as illustrated in FIG. 3, the slit 3 a isformed perpendicularly when the face surface is set perpendicularly tothe ground. A width t₂ (slit thickness) in the back-to-forth directionof the slit 3 b is even throughout the entire length thereof. Accordingto this embodiment, a thickness t₁ of the front face portion on a faceside relative to the slit 3 a is smaller than a thickness t₃ of the rearface portion, and although the slit 3 a may be located slightly on theface side with respect to a center in the thickness direction of theface insert 3, the slit 3 a may be located at the center. Preferably,the ratio of the thickness t₂ of the slit 3 a with respect to a totalthickness (t₁+t₂+t₃) of the face insert 3 is 10 to 50%, and morepreferably 25 to 45%, and the ratio of the thickness t₁ is preferred tobe 10 to 50% and more preferably 25 to 40%.

This slit 3 a may be formed easily by cutting a sheet metal for the faceinsert 3. When forming the face insert 3 with synthetic resin, the slit3 a may be formed at the same time when the face insert is molded with aconvex portion corresponding to the slit 3 a prepared in an injectionmold using a core or the like. The face insert 3 is disposed within therecess portion 2H such that a left side face in FIG. 3 acts as theforward side of the face of the putter, and bonded to the wall surfaceon the deep side of the recess portion 2H with adhesive. Although as theadhesive, epoxy base adhesive, rubber base adhesive and double-sidedadhesive tape are preferably used, the present invention is notrestricted to these examples.

By connecting a shaft to a hosel part 1 h of the putter head 1 havingsuch a configuration, the putter is constructed. When putting a ballwith this putter (hitting the ball on a green with the face surface),the front face portion (forward side relative to the slit 3 a) of theface insert 3 is slightly retracted. As a result, the top spin is easilyapplied to the ball, whereby the straight advancement of the hit ballbeing improved. Furthermore, the characteristic of deformation of thefront face portion of the face insert 3 is hardly affected by a changein temperature, so that easiness of applying the top spin hardly dependson the temperature.

According to the present invention, as illustrated in FIG. 5, the slit 3a may be filled with a viscoelastic body 3 b. As the viscoelasticmaterial, rubber, elastomer, soft synthetic resin and the like areavailable. By filling the slit 3 a with viscoelastic material, a hittingsound and a feeling of hitting the ball can be adjusted. Thisviscoelastic material hardly affects the deformation characteristic ofthe front face portion of the face insert, so that the easiness ofapplying the top spin hardly depends on the temperature.

In the face insert 3 of the above-described embodiment, the ceiling faceof the slit 3 a is foamed in the shape of a semielliptical arch from thetoe side to the heel side, and this arch shape lowers in heightconsecutively from the vicinity of the center in the toe-to-heeldirection toward the heel side (i.e., the slit 3 a becomes shallowergradually). However, like a face insert 3A in FIG. 6, the ceiling facemay be descended by step from the vicinity of the center in thetoe-to-heel direction toward the heel side. Furthermore, while the depthof the slit 3 a may be constant along the toe-to-heel direction aroundthe center in the toe-to-heel direction thereof like a face insert 3B inFIG. 7, the slit 3 a may be formed to be shallower gradually (or bystep) toward the toe side and the heel side in areas near the toe andthe heel.

According to the present invention, like a face insert 3D in FIG. 8, theslit 3 a may be provided with shallow grooves 3 d which communicate withan end face on the toe side of the face insert 3D and an end face on theheel side thereof Preferably, a depth H₂ of the shallow groove 3 d is20% or less a height H₀ of the face insert 3D, more particularly to 15%or less. If H₂ is increased excessively (e.g., if H₂ is set equal to theaforementioned H₁), a repelling force of a ball when hitting the balldrops. If H₂ is set to 20% or less (including 0%) H₀, the repellingforce of the ball increases, and consequently, a distance over which theball rolls is increased.

According to the present invention, as shown in FIG. 9( a), a faceinsert 3E may have a slit 3 a inclined forward such that its upperportion is located nearer the face side. In contrast, as shown in FIG.9( b), a face insert 3 f may have a slit 3 a inclined backward.

Although the front surface of the face insert is flat according to thisembodiment, a plurality of horizontally-extending grooves may beprovided in parallel. Preferably, a width (distance between the top andthe bottom) of each groove may be 0.3 to 1.6 mm and a depth of thegroove is preferred to be 0.05 to 1.1 mm.

Although the gap 4 is formed around the periphery of the face insert 3as illustrated in FIGS. 1( b) and 1(c), a viscoelastic material 8 suchas rubber, elastomer, synthetic resin, may be disposed in this gap. Likea putter head 1′ illustrated in FIG. 11, the face insert 3 may be formedto be fit to the recess portion 2H without any gap 4.

Other configurations of FIGS. 10 and 11 are the same as in FIG. 1 andlike reference numerals indicate like components. Provision of the gap 4and the viscoelastic material 8 between the side face 3S of the faceinsert 3 and the peripheral face 2S of the recess portion 2H ensures anadvantage that the repulsion characteristic of the face insert isrealized as designed.

1. A putter head having a face surface, comprising: a head main body;and a face insert disposed on the head main body as the face surface,wherein the face insert has a slit extending upward from a bottomsurface thereof, and wherein the face insert has a front face portionpositioned on a face-surface side relative to the slit and a rear faceportion on a backward side relative to the slit, the front and rear faceportions being connected to each other through toe and heel sides of theface insert.
 2. The putter head according to claim 1, wherein in thebottom face of the face insert, the slit extends from the vicinity of atoe-side end thereof up to the vicinity of a heel-side end thereof. 3.The putter according to claim 1, wherein the slit is deepest at acentral portion in a toe-to-heel direction of the face insert, and theslit becomes shallower gradually or step by step toward the toe side andthe heel side from the central portion thereof.
 4. The putter headaccording to claim 1, further comprising a viscoelastic materialdisposed in the slit of the face insert.